Your symptoms suggest that you are mostly experiencing metropathic cycles. This happens when there is hormone imbalance
. The irregular growth of the endometrium due to absence of the control in view of hormone imbalance leads to breakthrough bleeding
. As the vascular supply to the endometrium decreases, some of it is shed and this appears as brownish discharge. As blood supply recovers, bleeding is stopped. You need proper clinical evaluation, trans-vaginal sonogram, complete hormone profile, coagulation profile and urinalysis
to plan further management. Hormone supplements may be necessary to put the cycles back on track. Hope this helps.